Isobutylene-isoprene elastomers are used in the manufacture of adhesives, agricultural chemicals, fiber optic compounds, ball bladders, caulks and sealants, cling film, electrical fluids, lubricants (2 cycle engine oil), paper and pulp, personal care products, pigment concentrates, for rubber and polymer modification, for protecting and sealing certain equipment for use in areas where chemical weapons are present, as a gasoline/diesel fuel additive.
In many such applications, the high surface friction limits the use. In particular, molded articles such as gaskets, bladders, and seals are difficult to remove from molds, causing damage of the molded article and contamination of the mold. Many such molded articles require the use of additives to reduce the surface friction.
Typically, elastomers can demonstrate blocking behavior. The surface of the coating will not feel tacky but when two of the coated surfaces come in contact with one another, the coated surfaces show an affinity to each other and will adhere. Further, the elastomeric coatings can have increased frictional forces, or drag, between the elastomeric coating and an external surface.
Many conventional blocking agents are known, which are added to elastomers, or surface thereof, to reduce the surface friction and blocking. An anti-blocking agent, such as fatty alcohol, fatty alcohol esters and ethers as well as waxy polymers may be added to the elastomeric coating composition. Other waxy materials could also be used to reduce blocking. However, the conventional anti-blocking agents may reduce the overall elongation properties of the coating.
Silicones such as polydimethylsiloxane have been used to reduce the blocking behavior of elastomeric coatings. However, silicones are not compatible with most hydrocarbon elastomers such as butyl rubbers, and tend to phase-separate when coated, reducing the physical properties of the coatings. Further, due to the incompatibility, the silicones and elastomers tend to phase-separate when dissolved in organic solvents, rending uniform, homogeneous coatings difficult.